minor symfony#7290 Fixed a syntax issue in Doctrine article (javiereguiluz)

This PR was merged into the 2.7 branch.

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Fixed a syntax issue in Doctrine article

This fixes symfony@27aa549

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8e361ff Fixed a syntax issue in Doctrine article

Author: xabbuh

doctrine.rst

@@ -385,7 +385,7 @@ see the :ref:`doctrine-field-types` section.
 .. tip::
 
     After creating your entities you should validate the mappings with the
-    following command::
+    following command:
 
     .. code-block:: terminal